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I Patent Feb. 2,1Q2,

main eternal, or Basalt; swrrznnnenn.

No Drawing.

To all 71.;1097Lit may concern:

Be it known that I, Ran: mvan, a citizen of the Swiss Republic, of Basel, Switzerland,

- have invented a certain new and useful linproved Process of Dyeing Cellulose Acetates, of which the following is a, specification.

This invention relates to the dyeing of cellulose acetates in artificial silkjtilm or other form with development dyes or socalled ice colours. 1

it has been proposed to produce azo dyes on cellulose acetate goods by developmenton the fibre or material (see for example U. S. Paotppt 1,002,408 and British Patent; 24284 of 19 I In the technical application of the development dyes or so-called ice colours for dyeing cellulose acetates, such for example as cellulose acetate silks, fabrics, films or other goods, it has been found that practical'd veing to sample or standard is connected with" some difiiculties,inasmucb as after the application of the base to the cellulose acetate silk or goods it has been necessary to take out a specimen hank or skein or other corresponding specimen for diazotizing and developing. The dyeings so obtained were then compared with the sample, and according as thev turned out, the base or the'developing weakened. This sampling or matching required time, was rather diliicult to perform, and moreover required skilled dycrs.

In the present invention the cellulose acetate goods are dyed with development dyes by any of the following combinations or".

baths: (a) employing the bases and developors in one bath and diazo'tizing in a second bath, or (b) applying the base in one bath, diazotizinp, in the same bath and developing in a second bath, or (0) applying the base or developer in the first bath and diazotizing and coupling in the second bath, and accord ingto the invention. in effecting: the dyeing of the goods by any of these con'ibinations of baths. I employ protective colloids, such as boiled-oft lltllOl' (i. e, the liquor'resulting iron the boiling-off or degumming of raw .natural silk by boiling with soap solutions gelatine, and so forth to avoid precipitation or separation of bases, developers or dyestufl's by salting-out.

In any case it is seen thatapplication of two of the dye-forming factors: base, diazotization, and developer occurs in one bath and that of the third, factor in another bath.

bath had to be strengthened on Application tiled hotelier 5, "1922. Serial No. 592,602.

These various baths may be employedwith or without addition of a diazotizable or non-diazotizable dyestufi', and with or without acids and salts or any of these, but a protective co'lloid will always be employed n. at least one of the baths.

It has been found that it is possibleto work very guickly and well if one applies the base an developer in one bath, and if necessary adds. a dyestulf according to the shade required, and then diazotizes in a second bath, or if one applies the base, if necessary with a d estufh in one bathyand after some time ad etc this bath the'calculated or required uantity of nitrite and acid and then coup es with a developer in a second hat-h ;'the added dyestult may be diazotizable or non-diazotizable. Or one may work by impregnating the acetyl-celluloses either with'tlie-base or with the developer, and if desi red,'with a dyestuft, and afterwards diazotizing and coupling in a second bath.

Further, there may be-added to the baths, I in order to facilitate rapid absorption or taking up by the goods, acetic lactic or other organic or inorganic acids orwater-soluble sallts, preferably chlorides, or both acids and sa ts.-

In the first case, (a), where wehave b and developer in one bath, the operation may be as follower The cellulose acetates, for exam la in the form of hanks or skeins, are intro uced into the bath containing the base, developer and protective colloid and if desired an added dyes-tuft and turned therein. After sufiicient dyeing up, a small specimen hank or skein is removed from the bath, washed quickly and diazotized, the diazotizing bath consisting for example of sodium nitrite and. hydrochloric acid. It the dyed shade corresponds to the sample bank or skeinitheibatch is washed and diazotized; it it does not,.more base or moredeveloper or dyestutf is added to the before mentioned bath according to requirement, until a specimen skem corresponds to the requirements.

In the second case (7/), one may operate by first treating the goods with the base alone or together with a dyestuif, in the base bath. After moving the goods in the bath for some time, a spee-imen'hank is withdrawn, diazotized and developed, and according; to requirement one then adds more base or more dyestufi to the bath, afterwards diazotizing in the bath and developing 1n a second bath as before mentioned, a protective colloid being used in either or hot of the baths.

It has been found that no dimming or dulling of the acetate silk dyeing occurred by the addition of a basic diazotizationresisting dyestufi to the baseor developerbath, or base and developer bath, Whereas according to previous processes some dim: ining or dulling of the fibre has sometimes been caused by the diazotizing.

As before mentioned one may also operate arwrding to the third case, (0), by impregnating the cellulose acetate first in the developcror base-bath, washing, and then transferring to the base-diazotization or developer-diazotization bath, a protective colloid being used in'eit her or both baths.

Example I In order to dye 1' kg. of cellulose acetate silk a brown-red, the goods are introduced into a bath consisting of 25 liters water, 20 gr. amidoazobenzene, 30 gr. betanaphthol, 5 gr. Capri blue-e liters boiled-oft liquor. The goods are treated \for half an hour at ordinary temperature, aiidsthen 50 grams magnesium chloride are added-and the bath is heated to about C. After a further half hour, during which the cellulose acetate silk is repeatedly turned-in the bath, the goods are washed and transferred to the .diazotizing' bath.

This consists of 20 liters water,50 gr. sodii'un nitrite,-100 oc. concentrated hydrochloric acid. The goods are kept moving in the bath for half an hour at a low; temperature Then follow one washing with hard Water and one with soft water, and theme soapbath at 60 (3., followed by ,one washing with soft water. This is followed by th'elnsual brightening bath.

Eiwmple 1 kg. of cellulose acetate silk is introduced into a bath consisting of 25 liters water, 20.-

gr. amidoaz-otoluene, 2 liters boiled-off liquor. The Bath is heated at 60 C. and the goods are turned in it for about half an hour. Then SQ-"Tcc. technical sulphuric acid and 50 grams sodium nitrite are added to this bath and the goods airegdiazotized with repeated turning in the bath. After a further half hour the acetate silkis washed and entered into the developing bath at 60 0 consisting of 25 liters Water," 30 gr. betanaphthol, 50

in a second bath.

gr. soap. After an hour the goods are Washed and brightened.-

What I claim and desire to secure by Letters Patent isz- 1. In a process for dyeing cellulose acetates i'n artificial silk, film or other form by production of development dyes on the materiahapplying'two of the three dye-fornn ing factors: base, dianotizing means, and developer in one bath and the other factor in another bath, a protective colloid being employed in at least one of said baths.

2. In a process for dyeing cellulose ace tates in artificial silk film or other form by production of" development dyes on the material, applying two of the three dye forming factors: base, diazotizing means, and developer in one bath and the other factor in another bath, a protective colloid being elnployed'in at one of said baths, and an addeddyestutf being employed in at least one of the baths,

'3. In .a process for dyeing cellulose acetates in artificial silk, tihn or other form by production of development dyes on the material, applying two of the three dye-forming 'actors: base, diazotizing means, a id de- 'veloper in one bath and the other factor in another bath, a protective colloid being eniployed in at least one ct said baths, and an acid being also eniployd in at least one of saidbaths.

w 4, Ina nrocess for dyeing cellulose acetatesi'n artificial silk, film or other form by production of development dyes on the material, applying the 3:18?- and develo oer in one bath containing protective colloid, and diazot-izing in a second hath. I j

5. In a process of dyeing cellulose acetates in artificial silk, film or other forin by the production of shipment dyes on the material applying the base ed (ll" ."8l()]f)@l' in one bath c ntainin ii-active colloid, with addition of? a c.

i l CLAVEL.

base and developer suit, and diazotizing 

